If we assume a machine with all limit switches on one input and a separate input for each home switch and wire it up with any old decent Normally Closed micro-switch at end of travel we get home positions but with accuracy and repeatability which is often dismissed by owners of pro systems and rarely proves good enough to pick up halfway through a finishing operation.
But what if we add a cam somewhere on each stepper shaft or ball-screw which operates a second switch wired in parallel to the end of travel limit switch for that axis?
The cam switch will operate once per turn but the home circuit will only open with both switches open, tune the cam switch to open/close a fraction of a turn after the linearly actuated switch is open and the accuracy and repeatability should be significantly better than is achievable with just linear switching.
Sound feasible?
- Nick